[31.04] Some Dynamical Constraints on the Halo of NGC 3379 from Wide-Field Spectroscopy of Its Globular Cluster System

We present initial results from a study of the dynamics of
the outer halo of the nearby elliptical galaxy NGC 3379
based on wide-field spectroscopy of its globular cluster
system. Our study uses the FLAMES multi-object spectrograph
at the VLT to determine the radial velocities of candidate
gloublar clusters previously identified in CCD Mosaic images
of nearby elliptical galaxies. Over the large radial range
of 0.7 to 15 arcminutes (2 to 45 kpc) covered by our study,
the velocity dispersion of the globular cluster system
suggests the presence of a dark matter halo around NGC 3379,
consistent with the observed rotation of an HI ring at
larger distances. A less significant dark matter halo has
been suggested by studies of the planetary nebulae, and we
discuss possible reasons for this difference. SEZ and KLR
acknowledge support from NSF grants AST-0406891 and
AST-0302095 respectively.